The present invention relates to the field of decontamination of liquid or solid surfaces.
U.S. Pat. No. 4,366,067, French Patent No. 2,090,452, and European Patent No. 0,027,359 disclose articles intended to remove petroleum and oils present on the surface of a liquid. These articles include a wrapping or bag made of fabric or other material filled with birds' feathers, expanded perlite or closed-cell polyisocyanurate foam. However, the absorption of petroleum and of oils by these products is found to be clearly inadequate.
French Patent No. 2,288,709 describes a process for removing and recovering petroleum products, especially heavy hydrocarbons, spread on a liquid or solid surface, by bringing into contact with the petroleum product a finely divided polymer. The polymer produces with the petroleum product a film of sufficient strength to be pulled. The film is then removed by mechanical means.
A preferred polymer for use in this process is a polymer of bicyclo[2.2.1]-2-heptene or its methyl derivative. These polymers form with the petroleum hydrocarbons a coherent film which can contain up to 10 parts by weight of petroleum products per one part of polymer. According to this known process, the contact of the polymer with the petroleum product is brought about merely by sprinkling the polymer onto the surface of the product.
It has been found, however, that, in difficult meteorological conditions, which frequently prevail during emergency decontamination operations and especially in windy weather, it is disadvantageous to use these polymers by sprinkling them onto the sheets of petroleum products. A large part of the polymer powder is entrained outside the intended contaminated area and, consequently, reduces the effectiveness of the operation.
Moreover, in certain cases, especially that of transformer oils and that of light hydrocarbons such as domestic fuel oil, solvents, benzene, toluene and xylenes, the absorption capacity of the bicyclo[2.2.1]-2-heptene polymer can attain 15 and even 40 parts by weight of hydrocarbon per one part of polymer, while producing dry absorbates devoid of any subsequent sweating-out of the hydrocarbon, even under a pressure of 3 to 70 bars. However, such absorbates no longer have a sufficient cohesion to be capable of being removed in the form of a film which can be pulled. Rather, they tend to be semiagglomerated masses which are in the form of a gelatin. It is difficult to collect and remove this gelatin.
Finally, the use of the process according to French Patent No. 2,288,709 comes up against, on the one hand, the inadequacy of the kinetics of absorption of hydrocarbons and/or transformer oils by the bicyclo[2.2.1]-2-heptene polymer and, on the other hand, the aging of this polymer following prolonged storage.